<PRE><B>Question 390865</B>
First, find the total number of 5-digit numbers:


9*10*10*10*10 = 90000 (10 digits for each placeholder except the first)


Then, find the number of 5-digit numbers with *no* zeros (so that we can subtract from 90000 and find the number of 5-digit numbers with at least one 0):


9*9*9*9*9 = 59049 (9 digits for each placeholder)


90000 - 59049 = 30951.


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